1. Field of the Invention
This invention relates to a plasma display panel, and more particularly to a plasma display panel that is adaptive for improving a color coordinates correction and a color temperature.
2. Description of the Related Art
Generally, a plasma display panel (PDP) radiates a phosphorous material using an ultraviolet ray with a wavelength of 147 nm generated upon discharge of an inactive mixture gas such as He+Xe, Ne+Xe or He+Ne+Xe, to thereby display a picture including characters and graphics. Such a PDP is easy to be made into a thin-film and large-dimension type. Moreover, the PDP provides a very improved picture quality owing to a recent technical development. Particularly, since a three-electrode, alternating current (AC) surface-discharge PDP has wall charges accumulated in the surface thereof upon discharge and protects electrodes from a sputtering generated by the discharge, it has advantages of a low-voltage driving and a long life.
Referring to FIG. 1, a discharge cell of the conventional three-electrode, AC surface-discharge PDP includes a scan electrode Y and a sustain electrode Z provided on an upper substrate 10, and an address electrode X provided on a lower substrate 18.
The scan electrode Y includes a first transparent electrode 12Y, and a first bus electrode 13Y provided at the rear side of the first transparent electrode 12Y. The sustain electrode Z includes a second transparent electrode 12Z, and a second bus electrode 13Z provided at the rear side of the second transparent electrode 12Z.
The first and second transparent electrodes 12Y and 12Z are usually made from a transparent material so as to transmit a light from the discharge cell. At the rear sides of the first and second transparent electrodes 12Y and 12Z, the first and second bus electrodes 13Y and 13Z made from a metal material are provided in parallel to the first and second transparent electrodes 12Y and 12Z. The first and second bus electrodes 13Y and 13Z are used for applying driving signals to the first and second transparent electrodes 12Y and 12Z having a high resistance value. On the upper substrate 10 provided with the first transparent electrode 12Y and the second transparent electrode 12Z in parallel to each other, an upper dielectric layer 14 and a protective film 16 are disposed. Wall charges generated upon plasma discharge are accumulated into the upper dielectric layer 14. The protective film 16 prevents a damage of the upper dielectric layer 14 caused by a sputtering during the plasma discharge and improves the emission efficiency of secondary electrons. This protective film 16 is usually made from magnesium oxide (MgO).
A lower dielectric layer 22 and barrier ribs 24 are formed on the lower substrate 18 provided with the address electrode X. The surfaces of the lower dielectric layer 22 and the barrier ribs 24 are coated with a phosphorous material layer 26. The address electrode X is formed in a direction crossing the first transparent electrode 12Y and the second transparent 12Z. The barrier rib 24 is provided in parallel to the address electrode X to thereby prevent an ultraviolet ray and a visible light generated by a discharge from being leaked to the adjacent cells.
The phosphorous material layer 26 is excited by an ultraviolet ray generated during the plasma discharge to generate any one of red, green and blue visible light rays. An inactive mixture gas, such as He+Xe, Ne+Xe or He+Ne+Xe, for providing a gas discharge is injected into a discharge space defined between the upper and lower substrate 10 and 18 and the barrier rib 24.
In Such a PDP, the discharge cells sustain a discharge by the surface discharge between the scan electrode Y and the sustain electrode Z after they were selected by the opposite discharge between the scan electrode Y and the sustain electrode Z. The discharge cell of the PDP radiates the phosphorous material 26 by an ultraviolet ray generated upon the sustain discharge, thereby emitting a visible light into the exterior thereof. As a result, the PDP having the discharge cells displays a picture.
In such a conventional PDP, the phosphorous material 26 is excited by a vacuum ultraviolet ray Δ UV with a short wavelength produced upon discharge to generate a unique color visible light ray, thereby displaying red, green and blue colors R, G and B that are three initial colors of a light at each discharge cell. In the PDP, a color coordinates of a full white is greatly influenced by a substance of the phosphorous material 26 and a used inactive gas. For this reason, the phosphorous material 26 requires a coating over a wider area besides an improvement of its substance property and a uniform coating characteristic at the inner wall of the barrier rib.
To this end, the barrier rib coated with the phosphorous material 26 needs to have a structurally wide area. In other words, a stripe-type barrier rib 24 as shown in FIG. 2 has an advantage in that it does not have any structure for making a shut-off between the barrier ribs 24 to form a flowing path of an air, thereby making an air exhaust and a gas injection easily when an exhaust process of making the discharge space into a vacuum state for the sake of an injection of the mixture gas is performed. On the other hand, the PDP adopting the stripe-type barrier rib 24 has disadvantages in that it fails to have a high brightness characteristic because an amount of the visible light amount produced by a radiation of the phosphorous material 26 within the discharge cell is small due to a limitation in its area coated with the phosphorous material and in that a width of the gas flowing path between the upper and lower discharge cells is large due to a non-existence of the structure provided between the barrier ribs 24 at a region where the upper and lower discharge cells are divided, thereby causing a cross talk to lead to a color interference phenomenon between the pixels of the PDP.
In such a conventional PDP having such a stripe-type barrier rib 24, in order to achieve a color temperature improvement and a color coordinates correction, a structure of the stripe-type barrier rib 24 is provided in a non-symmetric shape to change a mutual area ratio among the discharge cell for implementing a red color R, the discharge cell for implementing a green color G and, the discharge cell for implementing a blue color B, thereby compensating a color coordinates based on a change in the light-emission area. In this case, the discharge cell for implementing the red color R has a higher light-emission brightness than the discharge cells for implementing the green color G and the blue color B, whereas the discharge cell for implementing the green color G has a higher light-emission brightness than the discharge cell for implementing the blue color B.
Accordingly, a distance (i.e., pitch) between the barrier ribs 28 for separating the red(R), green(G) and blue(B) discharge cells from each other is formed in a non-symmetric type to make a relationship of the blue(B)>the green(G)>the red(R), thereby adjusting a color coordinates of the full white. Therefore, a pitch of the discharge cell for implementing the blue color B has the largest size, and a pitch of the discharge cell for implementing the green color G has a smaller size than the blue(B) discharge cell and a larger size than the red(R) discharge cell. Thus, a pitch of the blue(B) discharge cell is increased to have a larger light-emission area than the symmetrical structure, thereby providing a color coordinates correction and a color temperature improvement.
However, the PDP in which a pitch between the discharge cells for implementing the red(R), green(G) and blue(B) colors has a non-symmetric structure has a problem in that horizontal pitches of the red(R), green(G) and blue(B) discharge cells are too reduced as a resolution of the PDP goes higher, thereby causing an increase of discharge voltage, a reduction of operation margin and a reduction of brightness/efficiency characteristics.